Sugar ring pucker: Difference between revisions
No edit summary |
No edit summary |
||
| Line 1: | Line 1: | ||
[[Sugar ring pucker]] refers to conformations of rings, particularly 5-membered rings. | [[Sugar ring pucker]] refers to conformations of rings, particularly 5-membered rings. | ||
<StructureSection load='' size='350' side='right' scene='90/900784/ | <StructureSection load='' size='350' side='right' scene='90/900784/Basepair/1'> | ||
==Envelope and twist conformations relieve ring strain== | ==Envelope and twist conformations relieve ring strain== | ||
For a 5-membered ring with perfectly tetrahedral geometry of each atom in the ring, there is minimal strain if the ring were planar (~355 degree rotation around the ring instead of 360). However, all hydrogens/substituents would be ecplised, which is not the lowest energy conformation.[https://www.sciencedirect.com/science/article/pii/B9780128128381500049] To relieve the strain, one or two atoms move out of the plane. The conformation with one atom out of the plane is called <scene name='90/900784/Cyclopentane/3'>envelope</scene> (endo or exo depending on whether the atom is above or below the plane). The conformation with two consecutive atoms out of the plane, one above and one below, is called twist. More than two atoms are never out of plane because the remaining three atoms always define a plane. | For a 5-membered ring with perfectly tetrahedral geometry of each atom in the ring, there is minimal strain if the ring were planar (~355 degree rotation around the ring instead of 360). However, all hydrogens/substituents would be ecplised, which is not the lowest energy conformation.[https://www.sciencedirect.com/science/article/pii/B9780128128381500049] To relieve the strain, one or two atoms move out of the plane. The conformation with one atom out of the plane is called <scene name='90/900784/Cyclopentane/3'>envelope</scene> (endo or exo depending on whether the atom is above or below the plane). The conformation with two consecutive atoms out of the plane, one above and one below, is called twist. More than two atoms are never out of plane because the remaining three atoms always define a plane. | ||